1. Field of the Invention
This invention relates to endless belts and, more particularly, to an apparatus for cutting individual belts from a belt sleeve having alternating ribs and grooves on a surface thereof to produce belts of uniform, predetermined width and cross-sectional configuration. The invention is also directed to a method of cutting the individual belts from the belt sleeve.
2. Background Art
Multi-ribbed V-belts are used in a wide range of devices, such as electric home appliances, information devices, etc. A typical multi-ribbed V-belt construction is shown in FIG. 6 herein at 10. The belt 10 has a body 12 which is endless in a lengthwise direction, indicated by the double-headed arrow 14. The body 12 has a constant width W between laterally facing side surfaces 16, 18. The body 12 is commonly made from a cast liquid urethane elastomer or a rubber elastomer. The rubber elastomer is generally at least of natural rubber, butyl rubber, styrene-butadiene rubber, chloroprene rubber, hydrogenated nitrile rubber, and alkylated chlorosulfonated polyethylene. The body 12 has embedded therein longitudinally extending load carrying cords 20 which may be made of polyester or nylon fibers to exhibit high strength and low elongation. The load carrying cords 20 are arranged at a suitable pitch between the side surfaces 16, 18.
The belt body 12 has an inside surface 22, through which V-shaped grooves 24 are formed. V-shaped ribs 26 are formed between adjacent grooves 24 in the widthwise direction of the belt 10.
Typically, the multi-ribbed V-belts 10 are constructed with a predetermined groove shape, size, and pitch. As an example, the assignee herein offers multi-ribbed V-belts made of urethane that are sold commercially under the trademarks RIBSTAR U(trademark) and POLYMAX(trademark), which have grooves with a shape and pitch as designated in Table 1, below.
The shape and pitch of grooves on multi-ribbed V-belts are designated according to International Standards (ISO-9982), as set out in Table 2, below.
A typical process for manufacturing multi-ribbed V-belts is as follows. Load carrying cords, which may be made from aramid fiber, polyester fiber, or the like, are spirally wound over a cylindrical internal mold which has axially extending ridges formed in the outer circumferential surface thereof at a suitable pitch in the circumferential direction. The internal mold is in turn fit within a cylindrical external mold, with a predetermined clearance maintained therebetween. The external mold has an internal surface with V-shaped grooves extending in a circumferential direction, with the grooves spaced at a predetermined pitch in the axial direction. The space between the external surface of the internal mold and the internal surface of the external mold is filled with a liquid elastomer and is degasified to cause the elastomer to set. The internal and external molds are then separated from each other to produce a belt sleeve having an exposed external surface with alternating ribs and grooves thereon.
Alternatively, the external mold can be made with an internal surface having no grooves formed therein i.e. with a flat surface. The belt sleeve resulting after separation of the internal and external molds can then be ground to produce the alternating ribs and grooves, which are formed by the external mold in the previously described method.
Predetermined widths of the belt sleeve are then serially removed to form individual multi-ribbed V-belts. The apparatus used to effect the cutting of the belt sleeve typically has a cutter which is pushed against the belt sleeve at the exposed surface where the ribs and grooves are formed.
The apparatus is designed to cut the belt sleeve precisely through the base of the V-shaped groove between adjacent ribs. The resulting cut produces side surfaces which each include a flat portion which is orthogonal to the back side surface of the belt and an angled surface portion which is contiguous with the flat surface portion and which projects laterally inwardly with respect to the belt body. If the cut between the adjacent ribs is laterally offset, one of two conditions occurs. First, the cut may be laterally shifted towards the center of the belt, as a result of which the area of the angled surface portion is reduced. This reduces the contact area between that surface portion and a cooperating pulley, potentially detrimentally reducing the overall transmission capability between the belt and cooperating pulley.
With the second condition, a part of the rib laterally outwardly from the outermost rib overhangs the angled surface portion. With this condition, the belt may not properly seat in a cooperating pulley. The overhanging rib portion may ride on top of the pulley so as to potentially cause the belt to disengage from the pulley and/or twist during operation.
In a typical belt construction, lateral shifting simultaneously produces one of these conditions at each lateral side of the belt. Thus, to ensure proper belt operation, it is important to accurately produce multi-ribbed V-belts of the same width and configuration.
In a typical belt cutting apparatus, the cutter is shifted laterally by a distance corresponding to the desired belt width after completion of each cutting operation. This distance is predetermined by the particular belt specification. Typically, manual inspection and adjustment of the cutter is carried out to produce the desired belt width. The groove within which the cut is to be formed, is commonly inspected by an operator using a magnifying glass. An instantaneous decision is made as to the deviation between the cutter location and the base/center line for the groove. The operator makes a quick lateral adjustment to eliminate the deviation between the center line of the groove and the cutting edge of the cutter, whereupon the cutting edge on the cutter is pressed into the belt sleeve material to effect removal of the belt.
In operations where the operator is required to continually inspect and make manual fine adjustments of the cutting edge, the operator may be required to become dedicated to a single task during the cutting operation. This may add significantly to the overall production costs and may adversely effect efficiency.
With this type of apparatus, if there is a deviation between the lateral location of the cutting edge on the cutter and the base of the groove at which a cut is to be made this deviation may recur each time that the cutter is moved after the completion of a cutting operation. In high speed, high production operations, this deviation must be compensated for instantaneously based on a quick visual observation by the operator and with a fine manual adjustment. To successfully make the adjustment both efficiently and accurately, the operator must generally be highly experienced and skilled. However, since the adjustment is based on a visual observation, even the skilled worker may not be able to consistently and effectively finely adjust the cutting edge on the cutter, as required. Inaccurate lateral location of the cutting edge results in the aforementioned problem, wherein one of the side surfaces of the belt has a reduced contact area, while the other side has a partial overhang of a rib portion.
These defects may become even more significant with belts having a groove pitch of 2 mm or less. Further, the defects with belts having a groove pitch of 2 mm or less may be more difficult to prevent. Still further, with these belts having a relatively small groove pitch, deviations from intended locations, even if relatively slight, may significantly affect production yield.
In certain cutting apparatus, the cutter is sequentially slid by the distance equal to the pre-programmed width of the belt being cut. Any deviation from the desired shiffing becomes aggravated by the fact that the error multiplies with each movement of the cutter. After a plurality of lateral movements of the cutter, a significantly greater deviation from the intended cutting location of the cutter edge may result. The deviation may be so significant that manual fine adjustment by the operator may not be sufficient to appropriately reposition the cutter blade. This may necessitate that the entire system be shut down and that more gross adjustments of the cutter be made.
The invention is directed to a cutting system including a belt sleeve, a support subassembly, a cutting subassembly, an imaging subassembly, and a control system. The belt sleeve has a body with a width between laterally spaced sides and which is to be cut at a predetermined cutting location on the body to form an individual belt. The belt sleeve is trained around the support assembly. The cutting subassembly includes a cutter having a cutting edge to engage and cut the belt sleeve at the predetermined cutting location. The cutting subassembly further has a base element which carries the cutter and which is repositionable to move the cutting edge in a lateral direction relative to the belt sleeve. The imaging subassembly generates an image of the actual lateral relationship between the cutting edge and the predetermined cutting location. The control system a) compares the image of the actual lateral relationship between the cutting edge and the predetermined cutting location to a reference image showing the preferred lateral relationship between the cutting edge and the predetermined cutting location b) determines a deviation between the actual lateral relationship between the cutting edge and the predetermined cutting location and the preferred lateral relationship between the cutting edge and the predetermined cutting location and c) generates a signal indicative of the deviation which can be processed to cause the base element to be repositioned to reduce the deviation between the actual lateral relationship between the cutting edge and the predetermined cutting location and the preferred lateral relationship between the cutting edge and the predetermined cutting location.
The support subassembly may include first and second spaced pulleys around which the belt sleeve is trained and a drive for causing the belt sleeve to move in an endless path around the first and second pulleys.
In one form, the imaging subassembly includes a camera and there is a monitor for displaying the image of the actual lateral relationship between the cutting edge and the predetermined cutting location generated by the camera.
In one form, the camera has an image pickup area with a center line and the cutting edges aligned with the center line of the image pickup area laterally with respect to the belt sleeve.
The cutting subassembly may include at least one cylinder for advancing the cutting edge against and through the belt sleeve.
The cutting edge and camera may be movable as one piece laterally relative to the belt sleeve.
In one form, the belt body has a plurality of ribs including first and second ribs with a V-shaped groove between the first and second ribs. The V-shaped groove has a base/center line which is at the predetermined cutting location.
In one form, the cutting subassembly includes a servomotor operable in a forward direction and a reverse direction to thereby selectively cause the base element to reposition in first and second opposite lateral directions relative to the belt sleeve and the servomotor is operable in response to the signal generated by the control system.
The control system may include a positioning sequencer for generating a signal that causes the servomotor to operate and move the base element laterally relative to the belt sleeve a distance corresponding to a desired width of an individual belt to be cut from the belt sleeve.
A mandrel may be provided that is selectively abuttable to at least one of the pulleys to reduce vibrations caused by the belt sleeve moving around the first and second pulleys.
In one form, the camera has an imaging pickup area with a center line and the cutting edge substantially coincides laterally relative to the sleeve with the cutting edge with the cutting edge engaged with the belt sleeve at the predetermined cutting location.
In one form, the belt sleeve has a plurality of endless grooves formed therein through a surface which is exposed with the belt sleeve trained around the support subassembly, the cutting edge is arranged to engaged the belt sleeve trained around the support assembly, the cutting subassembly includes at least one cylinder for advancing the cutting edge against and through the belt sleeve, the base element is guided in translation in a lateral direction relative to the belt sleeve trained around the support subassembly, the cutting edge and the at least one cylinder move with the base element in a lateral direction relative to the sleeve, the imaging subassembly has an imaging pickup area with the center line, and the predetermined cutting location is aligned laterally relative to the belt sleeve with a center line of the imaging pickup area.
The invention is also directed to a method of cutting an individual belt of a predetermined width from a belt sleeve having a width greater than the predetermined width using an apparatus having a support subassembly, a cutting subassembly including a cutting edge, an imaging subassembly, and a control system. The method involves the steps of training the belt sleeve around a part of the support subassembly, providing an image of a preferred relationship between the cutting edge and the predetermined cutting location along the width of the belt sleeve, through the imaging subassembly generating an image of the actual relationship between the cutting edge and the predetermined cutting location along the width of the belt sleeve, comparing the images of the preferred and actual relationships between the cutting edge and the predetermined cutting location along the width of the belt sleeve to determine a widthwise deviation between the preferred and actual relationships between the cutting edge and the predetermined cutting location along the width of the belt sleeve, based on the determined widthwise deviation repositioning the cutting edge widthwise relative to the belt sleeve to reduce the determined widthwise deviation, and after repositioning the cutting edge advancing the cutting edge into the belt sleeve trained around the part of the support subassembly.
The method may further include the step of moving the belt sleeve in an endless path as the cutting edge is advanced into the belt sleeve.
The method may further include the step of advancing a mandrel against the part of the support assembly to reduce vibration caused by the belt sleeve moving in the endless path.
The method may further include the steps of advancing the cutting edge fully through the belt sleeve to cut the individual belt from the belt sleeve and repositioning the cutting edge widthwise relative to the belt sleeve a distance corresponding to the predetermined width to a second predetermined location after cutting the individual belt from the belt sleeve.
The method may further include the steps of generating an image of the actual relationship between the cutting edge and a second predetermined cutting location, comparing the image of the preferred relationship to the image of the actual relationship between the cutting edge and the second predetermined cutting location to determine a second widthwise deviation between the preferred relationship and the actual relationship between the cutting edge and the second predetermined cutting location.
The method may further include the step of repositioning the cutting edge relative to the belt sleeve to reduce the second widthwise deviation.
The cutting edge may be advanced fully through the belt sleeve at the second predetermined cutting location.
The method may further include the step of repositioning the imaging subassembly widthwise relative to the belt sleeve before the cutting edge is repositioned widthwise relative to the belt sleeve toward the second predetermined cutting location.